In April 2019, the U.S. Supreme Court heard oral argument in a case that may call into question the constitutionality of a significant part of Arizona’s implied consent statute. The specific question posed by the case is whether a law that allows a blood test from an unconscious driver provides an exception to the Fourth Amendment’s warrant requirement.
Arizona’s implied consent statute provides that “a person who operates a motor vehicle in this state gives consent … to a test or tests of the person’s blood, breath, urine or other bodily substance.” The statute also states that “a person who is dead, unconscious or otherwise in a condition rendering the person incapable of refusal is deemed not to have withdrawn the consent … and the test or tests may be administered.”
The area of implied consent has always been controversial, but especially since 2013, when the Supreme Court issued an opinion in the case Missouri v. McNeely. In that case, the court held that the dissipation of alcohol in a DUI suspect’s blood is not an “exigent circumstance” that allows for a warrantless blood draw. Since then, the Court decided another landmark case, Birchfield v. North Dakota, in which the court held that warrantless breath tests are constitutionally permissible, but that blood draws require a warrant.